Mobile aerial tower

ABSTRACT

A mobile aerial tower incorporating an articulated boom having extensible boom elements mounted therein at least one of which is made of a dielectric material and with a rotatable and tiltable elbow carrying a personnel supporting platform at the extent of the same which is adjustably positioned on one of the boom elements and rotatably and tiltably mounted for positioning of the platform relative to the extendible boom elements.

ilnitefi @tates Patent [7 21 Inventors Orlo .1. Johnson Laltevilie; Albert E. Reske, Bloomington, both of Minn. [2]] Appl. No. 35,827 [22] Filed May 8, 1970 [45] Patented Jan. 4, 1972 [73] Assignee Tel-E-Lect, Inc.

Minneapolis, Minn.

[54] MOBILE AERIAL TOWER 24 Claims, 7 Drawing Figs.

[52] US. Cl 182/2 [51] Int. Cl B661 ll/04 [50] Field of Search 182/2, 141; 212/8, 144

[56] References Cited UNITED STATES PATENTS 2,735,365 2/1956 Bromberg 182/2 3,149,694 9/1964 Smithee... 182/2 3,203,503 8/1965 Smith 182/2 3,283,831 11/1966 Bronder 182/2 3,286,855 11/1966 Bill 182/2 Primary ExaminerReinaldo P. Machado Att0rneySchroeder, Siegfried & Ryan ABSTRACT: A mobile aerial tower incorporating an articulated boom having extensible boom elements mounted therein at least one of which is made of a dielectric material and with a rotatable and tiltable elbow carrying a personnel supporting platform at the extent of the same which is adjustably positioned on one of the boom elements and rotatably and tiltably mounted for positioning of the platform relative to the extendible boom elements.

PATENTEU JAN 4 B72 SHEET 1 [IF 2 Or/a J. Johnson m e h W W k N a w m E I f a e 5 m A O .& NQN Q% Qw KN 3w Qm Q\ .OQN 8 V E Q R N@ 8A QN Wm Gm .fl NW N h ON W J 7 r p hm n E u o bk Mm 0 NW o 0 Wk Q PATENTEDJAN 4 A/ben 5 Reske BY Or/o John a mg 2, gw

ATTORNEYS MOBILE AERIAL TOWER Our invention relates to mobile aerial towers and more particularly to an improved mobile aerial tower having an articulated boom with extensible members therein at least one of which is dielectric and with a rotatable and tiltable elbow carrying a personnel supporting platform or bucket thereon slidably mounted on one of the extensible elements.

In prior mobile aerial towers having associated therewith work platforms or personnel carrying buckets, personnel carrying bucket or platform have been mounted at the end of the tower or boom element some of which are pivoted on a main boom and others of which are telescopically mounted therein. This restricts the work function of the apparatus or tower to the positioning of personnel and does not provide additional elements on the boom structure by means of which other work functions may be performed. Consequently, such structures employ separate tower units for elevating apparatus, such as transformers or cross arms with respect to poles so that operators in the baskets or on the platforms may perform a work function.

In our prior copending application Ser. No. 3944, filed Jan. 19, 1970 and entitled ROTATABLE AND EXTENSIBLE ELBOW, an improved apparatus of this type is disclosed in which a platform or bucket is mounted on the end of a rotatable elbow carried by an extensible boom element or on the main boom of an articulated boom for a mobile aerial platform. The elbow location may be pivotally mounted on one of two elements of the boom structure selectively and the same will rotate in a plane parallel to the extent of the boom to position a platform or personnel carrying bucket in varying positions in the plane. The boom may be extensible and the elbow includes provisions for extending the same telescopically which enlarges the plane of rotation with respect to the end of the boom element but the relative spacing between the plane of rotation and the boom extension remains fixed, restricting movement of the occupants of the basket or platform and the work function they can perform thereon.

In our present invention, an improved mobile aerial tower is provided in which the boom includes extensible sections at least one of which is made of a dielectric material and each are relatively movable with respect to one another and the main boom. In addition the boom mounts an elbow carrying a work platform or personnel bucket at the end of the same which elbow is adjustably positioned at varying points along the extent of one of the extensible elements and with the elbow in turn being pivotally mounted along its extent so that the extremity of the same may tilt transverse to the extent of the elbow and toward and away from the extensible element for adjustably positioning the platform or bucket relative to the extremity of the extensible element and with respect to any work being carried on by the extensible element. The bucket or platform is in turn rotatably mounted on the end of the elbow so that it will maintain a fixed position with respect to gravity as the elbow is rotated and with additional provision for maintaining a predetermined relationship with respect to the extensible element as the elbow is tilted. The structure provides for control of all of the functions of the boom and any work function to be carried on by the extensible elements from the position of the platform with improved positions for directing fluid control and power lines thereto.

Therefore it is the principal object of this invention to provide an improved mobile aerial tower having an extensible boom element and a rotatable and tiltable platform or bucket carrying elbow mounted thereon.

Another object of this invention is to provide in a mobile aerial tower of this type an arrangement by means of which the elbow and platform may be adjustably positioned along the extent of the boom structure and tilted relative thereto for accessibility to the occupants of the platform.

A further object of this invention is to provide in a structure of this type an improved arrangement of parts by means of which the platform may be maintained in a predetermined reference with respect to the extensible element for all degrees of elbow movement.

Another object of this invention is to provide a structure of this type in which the controls for the actuators controlling movement of the boom and elbow parts may be effected from the platform positioned through controls thereon.

These and other objects of this invention will become apparent from the reading of the attached description together with the drawings wherein:

FIG. 1 is a side elevation view of a mobile aerial tower embodying our invention,

FIG. 2 is a top view of a portion of the boom and extensible elements of the mobile aerial tower of FIG. 1, taken along the lines 2-2 therein,

FIG. 3 is a top elevation view of a portion of the rotatable and tiltable elbow member of FIG. I, taken along the lines 3 3 therein,

FIG. 4 is a partial side elevation view of a portion of the rotational elbow and its support with parts removed to show the drive of the same,

FIG. 5 is a sectional view of the rotatable coupling for the elbow as taken along the lines 5-5 in FIG. 3,

FIG. 6 is a top view of a portion of the elbow with part broken away to show mounting of the tiltable section thereof, and

FIG. 7 is a side elevation view of the boom with parts removed to show control lines positioned therein.

Our invention in a mobile aerial platform with a tiltable and rotatable elbow is shown in side elevation in FIG. 1 to show relationship of parts. Such a structure is normally carried by a conventional truck chassis which includes not only for the support for the same but selfcontained power source equipment of the hydraulic type to control and supply the operators or actuators of the boom structure. Thus in FIG. 1, the boom structure is indicated generally at 10 as shown mounted on a portion of the chassis, indicated generally at 11, as the type of equipment which normally supports and mounts the same. The details of this type of equipment form no part of the present invention except as to provide a mobile source and support for the boom structure. Positioned on the fragmentary showing of a portion of the chassis 11 is a supporting frame I2 which supports and mounts the turntable 14 or platform upon which the main boom element 16 of the boom structure is pivotally mounted, as at 15. The platform will normally be driven or rotated in azimuth about a vertical axis through 360 rotation through suitable drive means (not shown). In addition the main boom structure 16 is oriented or pivoted in a vertical plane relative to the turntable through actuators indicated generally at 18. This portion of the structure is largely conventional and may vary in form. Although not shown, it will be recognized that in addition to the power source and power equipment for this portion of the boom a secondary set of controls is normally included on the chassis for operating the structure independent of an operator on a platform positioned on the end of a boom structure.

As indicated in FIG. 1, the main boom element I6, in this type of boom structure, mounts a second or extensible boom element 20 which telescopically fits within the same and is joumaled to slide therein through roller means I9. Movement of this first extensible boom element 20 relative to the main boom element 16 is effected by means of an actuator including a cylinder 22 connected to and positioned below the main boom element and having an operating shaft 24 connected to the end of the extensible element 20. This is a long stroke linear actuator of the hydraulic type, preferably. The first extensible boom element 20 mounts a second extensible boom element 30 within the same in a telescopic manner which boom element is extended and retracted through an internally mounted linear actuator (not shown) of the long stroke type and normally a hydraulic actuator. The main boom element 16 together with the supporting structure for the same and the first extensible boom element 20 together with the mountings for the same are normally metallic while the inner or second extensible boom element 30 will normally be made of a dielectric material to insulate the same from the remaining portion of the boom structure when working under electrical lines or equivalent hazardous conditions. The second extensible boom element mounts a winch or pulley 40 at the extent of the same. As will be seen in FIG. 1, the boom structure carries, in addition to the extensible elements and 30, a personnel carrying platform indicated generally at 50. The latter is mounted through an elbow member indicated generally at 60 which in turn is rotatably mounted on a supporting and mounting bracket 70 for continuous rotation through 360and greater and in reversible directions, the latter as will be hereinafter noted, being slidably mounted on the extensible element 20.

As will be seen in F I68. 1 and 2 the elbow or mounting arm 60 for the platform 50 is pivoted along its extent to provide a rotatable arm section or portion 62 and a pivoted arm section or portion 64 with a pivot structure indicated at 65 positioned therebetween. The portion 42 may be made of metal and the end or arm section is preferably made of a dielectric material. The entire arm or elbow is rotatably mounted on the mounting bracket or spinner 70 and is journaled for 360rotation, being driven by a separate motive means, to be hereinafter described. Similarly, the platform 50 is rotatably mounted on the end of an elbow or arm 60 for rotation about an axis parallel to the axis of rotation of an arm 60 on the spinner or mounting bracket 70, as will be hereinafter identified. In addition, the platform and its rotational mounting is pivotally mounted on the end of the elbow portion 64, as indicated at 68, about an axis parallel to the axis of pivot of the mounting 65 for the purpose of maintaining a predetermined orientation between the platform and the rotatable portion of the elbow as will be hereinafter described. In addition, the support mounting bracket for the elbow 60 or that structure indicated generally at 70 includes a housing 72 which is slidably mounted on the extensible boom element 20 through journal means 74 to be movable along the extent of the extensible element in varying extended or retracted positions. A linear hydraulic actuator, indicated generally at 75, having a cylinder 76 and an operating shaft 77 is connected respectively between the casing 72 and a flange 78 on the boom structure or main boom element 16 for the purpose of effecting such movement. The operating shaft 77 of the actuator 75 is attached through a pivotal connection 79 to the flange 78 on the boom element 16 with the cylinder extremity being connected to the casing 72 of the spinner.

As will be best seen in FIG. 2, the housing 72 includes a mounting for the reversible drive motor 80 of the spinner which is mounted on a casing part and includes a speed reducer 82, the same driving a drive gear 85 (see FIG. 4) which cooperates with gearing (not shown) within the casing coupling the casing to the drive rotatable arm section 62 of the elbow to rotate the same. The structure also includes a rotary coupling assembly 90 by means of which fluid connections are directed through a rotary mounting of the elbow on the spinner and down the elbow or arm member 64 to the platform controls. Input hydraulic power and control lines are directed through a manifold block assembly 95 on the housing and these are in part directed through the collector assembly and to the control valve actuators operating to move the rotatable elbow 60 and tilt the parts thereof. Similarly they include fluid lines directed to the internal actuator (not shown) which moves the extensible element 30.

The fragmentary top view and the side elevation view of the boom and its parts show the pivot structure 65 by means of which the rotatable elbow part 62 mounts the tiltable elbow part 64. The parts are moved relative to one another by a small linear actuator, indicated at 100. This actuator includes a cylinder 101 connected to the arm part 62 with its operating shaft 102 pivotally connected to a flange 104 carried by the end or tiltable portion 64 of the elbow. Extension or retraction of the linear actuator will tilt the end portion 64 through an arc of a limited number of degrees to either side of the alignment line of the elbow portions 62, 64. The actuator is set so that the parts are aligned when the actuator is in an intermediate position giving an approximate swing of to either side of the alignment line such that the platform may be moved closer to or away from the boom extremity and the plane of rotation of the elbow portion 62 for accessibility purposes. ln order that the platform 50 on the end of the tiltable elbow portion 64 may be maintained in a predetermined orientation with respect to the boom, that is parallel to the same, the platform and its journaling structure is pivotally mounted on the opposite extremity of the tiltable an'n portion 64 of the elbow through the pivot structure 68. A flange connected to the extremity of the elbow portion 62 at the pivot extremity 65 and extending normal thereto mounts a pair of tilt aligning arms 112, 114 which are pivotally mounted thereon and are connected to a similar flange indicated at carried by the collector block housing and rotary journaling structure mounting the platform 50. Thus any tilting movement of the arm portion 64 will be transmitted through the tilt aligning arms 112, 114 to the transversely extending flange 120 carried by the housing 130 which supports the platform and the same movement axially about the pivot 65 will be transmitted to the housing 130 about the pivot 68 and in an opposite direction so that the platform and its supporting housing will be tilted on the pivot structure 68 to maintain the platform parallel to the plane of rotation of the arm or elbow portion 62 and the extension or longitudinal axis of the extensible boom elements 20 and 30. This will maintain the operator thereon in a predetermined orientation with respect to any work being carried on by the winch or other work performing apparatus carried by the extremity of the dielectric boom section 30.

The platform 50 is journaled for free rotational movement about an axis extending normal to the extent of the elbow member so that it may move under the influence of gravity to be maintained in a vertical position with rotary movement of the elbow member 60. The housing 130 includes a rotational journal structure (not shown) and a rotary collector block. The latter is provided for the purpose of passing fluid connections through the rotary connection or mounting of the platform on the end of the elbow to tie the same to the controls located on the platform. A handoperated brake within reach of the operator on the platform frictionally engages the stationary portion of the housing to dampen or prevent sway of the platform relative to the elbow 60 as it is rotationally moved in the plane of movement and through operation of the motor 80 on the support bracket 70.

FIG. 5 shows a sectional view of a rotary collector block and journal mounting of the collector block 90 for the spinner. The same or substantially similar structure is employed in the casing 130. The stationary portion of the collector block 152 has a plurality of passages 155 therein which extend through the inner portion and meet with the plurality of ports 156 aligned with a group of grooved passages 160 on the interior surface of the opposite coupling part 170. The coupling part is enclosed in the housing and a plurality of ports communicating with the grooved passages 160, some of which are indicated at 180, have connected thereto fluid lines which lead down the elbow member and across the pivot structure 65 and 68 into the stationary portion of the collector block and mounting for the platform. The opposite coupling part has fluid lines which extend through a cabling to the controls 140 on the platform. Suitable journal bearings 195, 196 in the supporting housing journal stationary parts relative to the movable part and the inner portion of the rotary coupling is attached to the supporting housing (not shown). In this manner fluid power and control lines are directed from the platfonn along the extent of the elbow member and through the elbow supporting bracket 70 to permit rotary movement of these parts and tiltable movement of intermediate parts while maintaining continuity of the control and power lines. The fluid lines are directed through manifold blocks 200 and 95 respectively on the collector block housing 130 and bracket 70 such that the various power and/or fluid control lines may be directed from the boom structure and along the extent of thc extensible elements 20 and elbow 60 for control of the operators thereon.

FIG. 7 shows a portion of the main boom element 16 with parts removed to indicate hose extension and tension apparatus within the same for the purpose of supplying sufficient hose length to the fluid lines leading from the power source on the mast through a similar collector block (not shown) to the source of power and controls on the frame. Hose lines such as are indicated at 220, 230 and 240 are directed within the extent of the main boom element with certain of the lines, such as for example 230, 240 being directed across tensioning pulleys 250, 260 carried by a slidable pulley mounting 270 which in turn is adjustably positioned by means of a cable 285 extending across pulleys 277, 278 within the boom which cable is moved with the cylinder 76 upon extension and retraction of this actuator. Thus, sufficient hose lengths are provided for the hoses indicated generally at 230, 240, which may be a plurality of fluid lines, such that they may be maintained relatively taut and allowed to extend with the movement of the elbow support bracket 70 upon movement of its actuator to maintain sufficient hose length for proper hose length connection. The hose length 220 which would be a plurality of hoses leading to boom elements 20 and and then actuators would be directed within the boom elements 16 and 20 with a similar arrangement being directed to a hose extension and tension device in the boom element 16 to respond to movement of the extensible boom element 20 relative to the boom element 16. The broken portion of boom element 16 in FIG. 1 shows generally at 280 this similar arrangement of parts for hose length 220 with a cable 282 controlling hose length and pulley position, which cable extends through the boom and over cable guides 285 at the end of the boom element 16 and is connected to extensible element 20 to move therewith. These hoses lead to the actuator 22 for the boom element 20 and the internal actuator controlling the extension of the furthest or outermost boom element 30. Thus the hose lines as indicated by the cabling 230, 240 would be directed to the manifold 95 on the elbow mounting bracket 70, such that fluid power and control lines would be directed to the manifold which has associated therewith control valves (not shown) controlling fluid flow to actuators controlling the position of the platform on the boom structure and the position of the boom structure. Thus the boom may be extended or retracted and the elbow portion thereon extended or retracted along the extent of the first extensible boom element 20. lln addition tilt of the elbow and rotation of the same and tilt of the platform 30 is all controllable from the platform. The hose tension and extension devices and the rotary fluid coupling provide continuity in the fluid lines effecting control and power operation of the actuators on the boom structure with boom and elbow movements. Such hose extension and retraction structures, as well as the collector blocks, are conventional with this type of equipment and the details of the same may vary. They are disclosed herein only schematically and described only generally for the purpose of simplicity in disclosure.

in operation, our improved mobile aerial tower with a rotatable and tiltable elbow provides an arrangement by means of which the platform at the end of the same upon which the operator is mounted may be positioned relative to the extensible boom elements 20 and 30 of the tower so that the operator may perform various work functions from the platform and relative to equipment being handled by the extensible elements. The improved mobile aerial tower which is mounted on a mobile chassis will be oriented in azimuth through the conventional turntable l4 and pivoted vertically through operation of actuators controlling the position of the main boom element which carries the entire platform structure. This main boom element 16 will telescopically mount the extensible elements 20 and 30 with the main boom and first extensible element 20 being normally made of metal and with the second extensible element 30 being normally made of a dielectric material. A workperforming unit, such as a winch 35, may be mounted on the end of the dielectric extensible element 30 to perform varying work functions therefrom. The elbow mounting the platform or personnel carrying bucket is rotatably mounted for continuous rotation in either direction on a supporting bracket which bracket in turn is slidably mounted on the extensible element 20 and moved through operation of an actuator 75 to adjustably position the same along the extent of the first extensible element 20 with the same extended. Thus the position of the supporting structure for the platform will be adjustably positioned with respect to the end of the boom to bring the operator into proximity with the work being performed by the mobile tower from either direction. The rotatable elbow in turn is pivoted along its extent such that the platform at the end of the same may be positioned translationally of the plane of rotation toward and away from the extended boom elements for accessibility purposes. Thus the operator positioned on the platform may selectively move his position with respect to the end of the boom and any piece of equipment being carried thereby independent of any boom or work movement for improving working conditions. He may also lower the elbow and platform to the ground or supporting vehicle without changing the boom position to get tools or to leave the platform. The platform is held in a predetermined relationship with the end of the boom, that is parallel thereto through a linkage system which pivots the platform and its rotatable mounting so that the platform and its mounting will be tilted with tilt of the tiltable elbow portion 64. The elbow in turn is mounted for complete and continuous rotation in either direction on its supporting bracket or mounting structure through operation of a reversible rotatable hydraulic motor carried thereby so that the elbow may be moved in a plane and the platform moved into and out of the plane or to either side of the same for accessibility purposes. The platform operator will have at his disposal, controls to operate all of the elements of the mobile aerial tower with the hose lines being connected through the rotatable and extendable hose connections.

In considering this invention it should be remembered that the present disclosure is intended to be illustrative only, and the scope of the invention should be determined by the appended claims.

What is claimed is:

l. A mobile serial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one movably mounted extension boom member mounted on the articulated boom and including motive means for extending and retracting of same relative to the boom, a bracket mounted on the extensible boom member and including motive means for moving the same along the extent of the boom member, an elbow member rotatably mounted on the bracket, said elbow member including a rotatable portion and an end portion with the end portion being pivotally mounted on the rotatable portion for limited pivotal movement about an axis transverse to the rotational axis of the rotatable portion on the bracket for movement toward and away from the extensible boom member, and platform means pivotally mounted on the extremity of the end portion of the elbow member for rotative movement relative thereto.

2. The mobile aerial tower of claim 1 in which the articulated boom mounts a pair of extensible boom members telescopically fitted into one another and into the articulated boom with the outermost extensible boom member being made of a dielectric material and having pulley means thereon to guide a cable over the same.

3. The mobile aerial tower of claim 1 and including motive means connected between the end portion and the pivoted portion of the elbow member with the end portion being movable relative to the rotatable portion at an angle to either side of the extent of the same.

4. The mobile aerial tower of claim 1 and including a reversible rotatable motor mounted on the bracket and coupled to the rotatable portion of the elbow member through rotatable gearing to reversibly rotate the elbow member through 360 on the bracket.

5. The mobile aerial tower of claim 3 in which the motive means connected between the pivoted end and rotatable portions of the elbow member includes a linear actuator connected between the pivoted end and rotatable portions to pivot the end portion of the elbow member through a limited angular range of movement to either side of a reference defined by a line extending through the end and rotatable portions in aligned relationship.

6. The mobile aerial tower of claim in which the platform means mounted on the end portion of the elbow member includes a pivoted coupling parallel with the axis of pivot of the end portion on the rotatable portion of the elbow member and a rotatable axis normal thereto coupling the pivoted coupling to the platform means.

7. The mobile aerial tower of claim 6 and including belt crank means included in the pivoted coupling of the end portion with the platform and between the end portion and the rotatable portion of the elbow member with tie rod means connecting the belt cranks such that the platform means will pivot on the coupling in accord with movement of the end por tion relative to the rotatable portion of the elbow member and in opposite directions to cause the platform means to maintain a predetermined relationship with the boom and extensible boom members.

8. The mobile aerial tower of claim 5 in which the reversible motor on the bracket and the motive means on the elbow member together with the motive means for slidably moving the bracket on the extensible boom member are fluid actuators and including a rotary fluid coupling positioned on the bracket member and included in the pivotal mounting of the elbow member on the bracket member.

9. The mobile aerial tower of claim 1 and including hose coupling means extending from the boom member to the elbow member and the platform means at the extremity of the same with extendible and retractable guide means mounting the coupling hose within the boom member and the extensible boom member to permit extension and retraction of the same, with the coupling hose being directed through the rotary coupling on the bracket member.

10. The mobile aerial tower of claim 2 in which the motive means for the extensible boom member and the motive means for extending the bracket thereon are elongated linear actuators positioned extemal of the boom member and the extensible boom member and connected respectively between the boom member, the bracket and the extensible boom member for independent movement of the bracket on a boom member and the boom member relative to the extensible boom.

11. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one movably mounted extension boom member telescopically mounted in the articulated boom and including motive means for extending and retracting the same, a support bracket, means for adjustably positioning the support bracket at varying positions with respect to the articulated boom and the extensible boom member and along the extent of the same, an elbow member rotatably mounted on the support bracket, said elbow member including a reversibly rotatable portion movable in a fixed plane through 360of rotation with respect to the bracket and the articulated boom said elbow member including an end portion pivotally mounted on the rotatable portion and pivoted through limited angular rotation out of the plane of rotation of the rotatable portion and about an axis normal to the axis of rotation of the elbow member, and platform means pivotally mounted on the extremity of the end portion of the elbow member for rotative movement thereon.

12. The mobile aerial tower of claim 11 and including means pivotally mounting the rotatable platform means on the extremity of the tiltable end portion of the elbow member for limited pivotal movement thereon and including means coupling the rotatable portion with the rotatable platform means such that the platform means maintains a predetermined angular relationship with the rotatable portion during tilting pivotal movement of the end portion of the elbow member.

13. The mobile aerial tower of claim 12 in which the means for ad'ustabl sitionin the su ort bracket includin ournal miaans slidably mouiting th e bracket on the exte n sible boom member and including motive means for extending and retracting the same thereon.

14. The mobile aerial tower of claim 13 in which the articulated boom includes a pair of slidably mounted extension boom members telescopically mounted in the articulated boom with the inner boom member being made of a dielectric material and including means at the extremity of the same for performing a work function.

15. The mobile aerial tower of claim 14 including control means positioned on the platform means and connected through the elbow member and the bracket and controlling operation of the articulated boom, the motive means for the extensible boom members, i of the bracket and the elbow member.

16. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one additional boom member movably mounted on the articulated boom and including motive means for moving the same relative to the articulated boom, a bracket mounted on the additional boom member and including means for moving the same along the extent of the additional boom member, an elbow member rotatably mounted on the bracket, motive means for driving the elbow member relative to the bracket through a continuous rotative movement with respect thereto, and platform means pivotally mounted on the extremity of the elbow member for rotative movement relative thereto.

17. The mobile aerial tower of claim 16 and including means included in the elbow member for altering the orientation of the platform means at the end of the elbow member relative to the movable second boom member.

18. The mobile aerial tower of claim 17 in which the means included in the elbow member is a portion of the elbow member with the platform connected thereto which may be moved translationally of the rotation of the elbow member on the bracket means.

19. The mobile aerial tower of claim 16 in which the elbow member with the platform thereon may be moved independently of the movement of the movable second boom member.

20. The mobile aerial tower of claim 18 and including means coupling the platform means to the elbow means for maintaining a predetermined orientation of the platfonn means with the bracket mounting the elbow means with translational movement of the portion of the elbow means carrying the platform.

21. A mobile aerial tower comprising, a mobile platform, a boom member mounted on the platform, an elbow member, support bracket means rotatably mounting the elbow member on said boom member, power means carried by the boom and connected to the elbow member for rotating the same in a vertical plane on the bracket for continuous rotation, a personnel carrying means carried at the free end of the elbow member, and means included in the elbow means intermediate the extent of the same for pivoting a portion of the elbow member with the personnel carrying means thereon translationally of the vertical plane of movement of the elbow member.

22. The mobile aerial tower of claim 21 and including further means included in the elbow member and in the personnel carrying means for maintaining the personnel carrying means in a predetermined position relative to the support bracket means with translational movement of the portion of the elbow member and the personnel carrying means.

23. The mobile aerial tower of claim 22 in which the means mounting the bracket on said boom member includes means for movably mounting the same thereon for movement longitudinally thereof.

24. The mobile aerial tower of claim 16 in which the motive means is reversible to drive the elbow member in either direction of rotation with respect to the bracket. 

1. A mobile serial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one movably mounted extension boom member mounted on the articulated boom and including motive means for extending and retracting of same relative to the boom, a bracket mounted on the extensible boom member and including motive means for moving the same along the extent of the boom member, an elbow member rotatably mounted on the bracket, said elbow member including a rotatable portion and an end portion with the end portion being pivotally mounted on the rotatable portion for limited pivotal movement about an axis transverse to the rotational axis of the rotatable portion on the bracket for movement toward and away from the extensible boom member, and platform means pivotally mounted on the extremity of the end portion of the elbow member for rotative movement relative thereto.
 2. The mobile aerial tower of claim 1 in which the articulated boom mounts a pair of extensible boom members telescopically fitted into one another and into the articulated boom with the outermost extensible boom member being made of a dielectric material and having pulley means thereon to guide a cable over the same.
 3. The mobile aerial tower of claim 1 and including motive means connected between the end portion and the pivoted portion of the elbow member with the end portion being movable relative to the rotatable portion at an angle to either side of the extent of the same.
 4. The mobile aerial tower of claim 1 and including a reversible rotatable motor mounted on the bracket and coupled to the rotatable portion of the elbow member through rotatable gearing to reversibly rotate the elbow member through 360* on the bracket.
 5. The mobile aerial tower of claim 3 in which the motive means connected between the pivoted end and rotatable portions of the elbow member includes a linear actuator connected between the pivoted end and rotatable portions to pivot the end portion of the elbow member through a limited angular range of movement to either side of a reference defined by a line extending through the end and rotatable portions in aligned relationship.
 6. The mobile aerial tower of claim 5 in which the platform means mounted on the end portion of the elbow member includes a pivoted coupling parallel with the axis of pivot of the end portion on the rotatable portion of the elbow member and a rotatable axis normal thereto coupling the pivoted coupling to the platform means.
 7. The mobile aerial tower of claim 6 and including belt crank means included in the pivoted coupling of the end portion with the platform and between the end portion and the rotatable portion of the elbow member with tie rod means connecting the belt cranks such that the platform means will pivot on the coupling in accord with movement of the end portion relative to the rotatable portion of the elbow member and in opposite directions to cause the platform means to maintain a predetermined relationship with the boom and extensible boom members.
 8. The mobile aerial tower of claim 5 in which the reversible motor on the bracket and the motive means on the elbow member together with the motive means for slidably moving the bracket on the extensible Boom member are fluid actuators and including a rotary fluid coupling positioned on the bracket member and included in the pivotal mounting of the elbow member on the bracket member.
 9. The mobile aerial tower of claim 1 and including hose coupling means extending from the boom member to the elbow member and the platform means at the extremity of the same with extendible and retractable guide means mounting the coupling hose within the boom member and the extensible boom member to permit extension and retraction of the same, with the coupling hose being directed through the rotary coupling on the bracket member.
 10. The mobile aerial tower of claim 2 in which the motive means for the extensible boom member and the motive means for extending the bracket thereon are elongated linear actuators positioned external of the boom member and the extensible boom member and connected respectively between the boom member, the bracket and the extensible boom member for independent movement of the bracket on a boom member and the boom member relative to the extensible boom.
 11. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one movably mounted extension boom member telescopically mounted in the articulated boom and including motive means for extending and retracting the same, a support bracket, means for adjustably positioning the support bracket at varying positions with respect to the articulated boom and the extensible boom member and along the extent of the same, an elbow member rotatably mounted on the support bracket, said elbow member including a reversibly rotatable portion movable in a fixed plane through 360* of rotation with respect to the bracket and the articulated boom said elbow member including an end portion pivotally mounted on the rotatable portion and pivoted through limited angular rotation out of the plane of rotation of the rotatable portion and about an axis normal to the axis of rotation of the elbow member, and platform means pivotally mounted on the extremity of the end portion of the elbow member for rotative movement thereon.
 12. The mobile aerial tower of claim 11 and including means pivotally mounting the rotatable platform means on the extremity of the tiltable end portion of the elbow member for limited pivotal movement thereon and including means coupling the rotatable portion with the rotatable platform means such that the platform means maintains a predetermined angular relationship with the rotatable portion during tilting pivotal movement of the end portion of the elbow member.
 13. The mobile aerial tower of claim 12 in which the means for adjustably positioning the support bracket including journal means slidably mounting the bracket on the extensible boom member and including motive means for extending and retracting the same thereon.
 14. The mobile aerial tower of claim 13 in which the articulated boom includes a pair of slidably mounted extension boom members telescopically mounted in the articulated boom with the inner boom member being made of a dielectric material and including means at the extremity of the same for performing a work function.
 15. The mobile aerial tower of claim 14 including control means positioned on the platform means and connected through the elbow member and the bracket and controlling operation of the articulated boom, the motive means for the extensible boom members, of the bracket and the elbow member.
 16. A mobile aerial tower comprising, a mobile platform, an articulated boom mounted on the platform, at least one additional boom member movably mounted on the articulated boom and including motive means for moving the same relative to the articulated boom, a bracket mounted on the additional boom member and including means for moving the same along the extent of the additional boom member, an elbow member rotatably mounted on the bracket, motive means for driving the elbow member relative to the bracket through a continuous rOtative movement with respect thereto, and platform means pivotally mounted on the extremity of the elbow member for rotative movement relative thereto.
 17. The mobile aerial tower of claim 16 and including means included in the elbow member for altering the orientation of the platform means at the end of the elbow member relative to the movable second boom member.
 18. The mobile aerial tower of claim 17 in which the means included in the elbow member is a portion of the elbow member with the platform connected thereto which may be moved translationally of the rotation of the elbow member on the bracket means.
 19. The mobile aerial tower of claim 16 in which the elbow member with the platform thereon may be moved independently of the movement of the movable second boom member.
 20. The mobile aerial tower of claim 18 and including means coupling the platform means to the elbow means for maintaining a predetermined orientation of the platform means with the bracket mounting the elbow means with translational movement of the portion of the elbow means carrying the platform.
 21. A mobile aerial tower comprising, a mobile platform, a boom member mounted on the platform, an elbow member, support bracket means rotatably mounting the elbow member on said boom member, power means carried by the boom and connected to the elbow member for rotating the same in a vertical plane on the bracket for continuous rotation, a personnel carrying means carried at the free end of the elbow member, and means included in the elbow means intermediate the extent of the same for pivoting a portion of the elbow member with the personnel carrying means thereon translationally of the vertical plane of movement of the elbow member.
 22. The mobile aerial tower of claim 21 and including further means included in the elbow member and in the personnel carrying means for maintaining the personnel carrying means in a predetermined position relative to the support bracket means with translational movement of the portion of the elbow member and the personnel carrying means.
 23. The mobile aerial tower of claim 22 in which the means mounting the bracket on said boom member includes means for movably mounting the same thereon for movement longitudinally thereof.
 24. The mobile aerial tower of claim 16 in which the motive means is reversible to drive the elbow member in either direction of rotation with respect to the bracket. 